The present invention concerns, first, apparatus for supplying viscous blends, casting resins for example, of two or more components that react and cure when blended, preferably in a vacuum. The apparatus comprises
a) one holding tank for each component, PA1 b) a set of flow controls downstream of each holding tank, PA1 c) a valve, a check valve for example, in or downstream of each set of flow controls as necessary, PA1 d) a line downstream of each set of flow controls or of each check valve, PA1 e) blenders communicating with each line, and PA1 f) an injector downstream of each blender and supplying the blend to a compression-setting mold for example, PA1 a) one holding tank for each component, PA1 b) a set of flow controls downstream of each holding tank, PA1 c) a valve, a check valve for example, in or downstream of each set of flow controls as necessary, and PA1 d) a closed loop downstream of each set of flow controls and check valve and leading up to each blender and then back to the holding tank, whereby PA1 e) each loop extends through FORWARD/DIVERT valves with one intake and two alternatively opening and closing outlets, one outlet forwarding the component on through the loop and the other outlet diverting it out of the loop to one of the blenders. PA1 1. first, the flow controls continue supplying each loop with its particular component until it is fully charged and the component is returning to the holding tank, PA1 2. second, the FORWARD/DIVERT valves that divert the components to a particular blender disestablish communications with the loops and divert the components flowing through the loops to the blender PA1 3. third, the flow controls remain in operation until the blender contains a specific volume of the components, PA1 4. fourth, the first and second steps are repeated with at least one more blender, PA1 5. fifth, the blenders proceed to blend the components and if necessary condition the blend, and PA1 6. sixth, the blend is introduced into molds, compression-setting molds for example, through the injectors.